Vodafone continues to have the highest proportion of customer complaints to the Telecommunications Industry Ombudsman (TIO), according to the latest statistics, but Optus has reported a significant decline on the back of changes it made to customer billing.

The figures, published on the TIO's website this morning, following the release of broader statistics overnight, show that Telstra and Vodafone saw a rise in the number of complaints in the first quarter of 2013, compared to the last three months of 2012, but Optus saw a significant drop overall when combining Optus Networks, Optus Mobile, and Optus Broadband.

Company

Complaints Oct-Dec

Complaints Jan-Apr

Telstra

13,431

14,579

Vodafone (including 3)

10,287

11,215

Optus

7,539

6,135

Virgin Mobile (Optus subsidiary)

1,858

1,548

Telstra topped the list of the number of complaints, and also had the biggest rise, adding an extra 1,148 new complaints for the quarter. Vodafone came in second, with 987 additional new complaints in the quarter. Optus fared best, with 1,404 fewer complaints in the quarter, and Optus' subsidiary Virgin also saw a drop in complaints in the quarter.

Telstra is always likely to have the highest number of TIO complaints, given that its customer base is significantly larger than either Optus' or Vodafone's, with 14.4 million mobile customers, compared to over 9 million with Optus and over 6 million with Vodafone. However, the results show that proportionally, Vodafone is still receiving the most complaints to the TIO.

Vodafone CEO Bill Morrow has said previously that the company is now working to address those high numbers, and expects there to be a turnaround later this year, with the aim to eventually have the lowest number of complaints to the TIO.

A Vodafone spokeswoman said that its complaint levels are trending downwards year on year, but said that more could be done to improve it.

"Vodafone's customer service is getting better all the time, and while we acknowledge that any customer that isn't able to have their issue resolved directly by our care teams is not good, we are encouraged by the fact our complaint levels to the TIO have dropped more than 35 percent in the past two years," the spokesperson said.

The 18.6 percent drop in complaints to Optus coincided with a change in how Optus charged customers who exceeded their monthly caps. As of September last year, customers who exceeded their monthly cap within Australia were not charged more than AU$200 in excess, while roaming customers from January this year were not hit with a bill larger than AU$500 for exceeding their monthly limit.

An Optus spokesperson said that the company has improved customer call procedures, including a proactive call back process for unresolved issues and new training for call centre staff in addition to the hard cap.

"These initiatives have been well received by our customers," the spokesperson said. "The focus for the coming quarter is introducing simple, transparent plans that are easy to understand and help minimise bill shock."

A Telstra spokesperson said that the company's customer complaints to the TIO year on year were trending down, and that extreme weather event periods such as that experienced by Australia over its summer can also see complaints go up.

"However, there is clearly still more work to be done in this area, and improving customer service remains our priority."

Outside of the three major telcos, TPG and Dodo were the most complained about, with TPG seeing a rise in the number of complaints from 834 in the last quarter of 2012 up to 1,181 in the first quarter of 2013, while Dodo saw a rise from 614 to 738.

Kogan Mobile also made its debut on the list in the first quarter of this year, seeing 312 complaints in the three months to the end of March, no doubt on the back of the dispute with wholesaler ISPOne, which saw hundreds of Kogan Mobile's customers unable to recharge their prepaid service after ISPOne deemed those customers to be in breach of the acceptable use policy.